Letters to the Editor

CLINICAL SIGNIFICANCE OF PROBENECID TEST

Concentrations of 5-hydroxyindoleacetic acid (5-HIAA) were determined in the lumbar cerebrospinal fluid (CSF) of patients after head injury. Unconscious patients showed after the fifth posttraumatic day no significant difference with the control group. The conscious patients showed significantly decreased 5-HIAA levels compared with the control group (following probenecid administration) as well as compared with the unconscious patients. These results suggest a relatively high cerebral serotonin turnover during the state of unconsciousness after head injury in man.

In biological research in depressions, antidepressants have served as a point of crystallization of working hypotheses that proved to be productive. Biological research in psychoses has so far made no use of neuroleptics, although in fact these agents could play a role similar to that of antidepressants in depression research. This, at least, is the theory advanced and advocated in this argumentation. With the neuroleptic drugs as a starting point, a strategy for biological research in psychotic disorders is outlined.

In this study electro-oculographic recordings were made after caloric vestibular stimulation (C.O.G.) in 42 patients with severe head-injuries. The curves with eyes open and the changes when eyes were closed were evaluated and scored. A correlation was found between the C.O.G. and the state of consciousness but only the degree of improvement of the C.O.G. showed a good correlation with the clinical improvement. The presence of a paradoxical response in patients with a prolonged coma was found to predict possibilities of further improvement. It was proposed that in the patients with a paradoxical response a rather diffuse biochemical dysfunction of the brain-stem was present, which could be influenced by treatment.

In the second part of this study the results of the trials with a treatment with L-Dopa and physostigmine are given. It was found that patients in a vegetative state or in a state of prolonged coma could be stimulated with the therapy only when the paradoxical response had been present. L-Dopa and physostigmine respectively improved the motor pattern and the contact activities.